With continuous improvement of requirements on a data transmission rate, communication quality, and the like of mobile communications nowadays, existing frequency bands used for mobile communications have become extremely congested. However, in a millimeter-wave band of 6 GHz to 300 GHz, a large quantity of spectrum resources are still not allocated for use. Introducing a millimeter-wave band into cellular access communications to make full use of high-bandwidth resources of the millimeter-wave band is one of research interests of a next-generation mobile communications technology.
In existing researches, a high frequency band represented by a millimeter-wave band is mainly applied to an indoor short-range communications scenario. In an outdoor scenario, because of characteristics of complex terrain of the outdoor scenario, a relatively large path loss of the high frequency band, a weak capability to penetrate obstacles, severe rain fade at some frequency bands, and the like, application of the high frequency band in the outdoor scenario is severely restricted. However, due to a short wavelength of the high frequency band, it is easy to implement a large-scale array antenna by using the high frequency band, and an antenna gain may be improved by using a beam forming technology, so as to effectively compensate for the large path loss of the high frequency band. This also makes it possible to apply the high frequency band to intermediate-to-long distance transmission in the outdoor scenario.
For high-frequency communications, line-of-sight (LoS) transmission can reach a specific transmission range. However, for non-line-of-sight (NLoS) transmission, a current research achievement indicates that high frequency data transmission in a specific range can also be implemented by using a reflection path. However, in an actual network environment, a line-of-sight path or a reflection path is easily blocked by some objects, and a blind area is formed. Consequently, communication quality is affected.